CHEMIMP: Chemical engineering plant models

Five matrices extracted from runs of the chemical engineering package SPEED UP. In each case, the matrix is the initial Jacobian approximation for a sparse nonlinear equation modeling a chemical process system.

Unsymmetric with many zeros on the diagonal. Some of the entries actually have the value zero. This happens when a procedure is used in which all outputs are incorrectly assumed to be a function of all inputs.

These matrices can be significantly reduced by block triangularization methods.